Project description:Currently, research on the impact of fertilizers on natural enemies, particularly spiders, is extremely limited. Most existing studies focus on field population dynamics and community structure, with scarce reporting on underlying mechanisms. This project, titled "Study on the Effects and Mechanisms of Urea on Predation Behavior of Farmland Spiders," integrates multidisciplinary theories and employs a combined approach of field investigations and laboratory experiments. It aims to Reveal the predatory strategies of dominant spider populations under chronic urea stress in agricultural ecosystems; to analyze the effects and mechanisms of chronic urea stress on predation-related metabolic, detoxification, and neuromodulation functions in dominant spider species from biological, physiological, cytomorphological, and multi-omics perspectives; to elucidate the comprehensive regulatory role and mechanisms of spider gut microbiota in mediating predation function responses to urea stress.Collectively, this research will clarify the impact and mechanisms of urea on the predation function of farmland spiders, providing a theoretical foundation and practical support for optimizing urea application in agricultural production and achieving the optimal comprehensive effects on spider predation services.
Project description:Spiders are renowned for their efficient capture of flying insects using intricate aerial webs. How the spider nervous systems evolved to cope with this specialized hunting strategy and various environmental clues in an aerial space remains unknown. Here, we report a brain cell atlas of >30,000 single-cell transcriptomes from a web-building spider (Hylyphantes graminicola). Our analysis revealed the preservation of ancestral neuron types in spiders, including the potential coexistence of noradrenergic and octopaminergic neurons, and many peptidergic neuronal types that are lost in insects. By comparing the genome of two newly sequenced plesiomorphic burrowing spiders with three aerial web-building spiders, we found that the positively selected genes in the ancestral branch of web-building spiders were preferentially expressed (42%) in the brain, especially in the three mushroom body-like neuronal types. By gene enrichment analysis and RNAi experiments, these genes were suggested to be involved in the learning and memory pathway and may influence the spiders’ web-building and hunting behavior. Our results provide key sources for understanding the evolution of behavior in spiders and reveal how molecular evolution drives neuron innovation and the diversification of associated complex behaviors.
Project description:We compare levels of gene expression in predator (Tigrosa helluo) exposed female Pardosa milvina compared to unexposed spiders and the offspring of predator exposed spiders to the offspring of control spiders.
Project description:Purpose: The goal of this study was to compare gene expression in whole embryos to identify transcriptomic changes that result from maternal exposure to predation risk. Methods: Whole embryo mRNA profiles of 3 day post-fertilizationstickleback embrosof mothers exposed to simulated predation risk and control embryos were generated by RNA-sequencing of pooled embryos using Illumina Hiseq2000. The sequence reads that passed quality filters were aligned to the stickleback reference genome and analyzed at the gene level (EdgeR) and at the transcript level (Cufflinks/Cuffdiff). Subsets of embryos were also measured for embryo length and eye diameter, and data were analyzed with a general linear model (SPSS). Results: We mapped ~22 million sequence reads per sample to the stickleback reference genome (BROADS1, Ensembl database version 71.1, Feb 2006) and identified 17440 transcripts with the Tophat workflow. Differential expression analysis using both EdgeR and Cufflinks/Cuffdiff identified 455 transcripts were differentially expressed in embryos of mothers exposed to simulated predation risk as compared to control embryos, with an FDR <0.05 (Cuffdiff) or <0.10 (EdgeR). Gene ontology and pathway analysis (DAVID, IPA) of the differentially expressed gene list revealed enrichment of genes involved in growth, metabolism, neurogenesis, and epigenetics. Embryos of mothers exposed to predation risk had elevated expression of growth and metabolism genes and were also larger than control embryos, suggesting at least some of the genes differentially expressed in this study are involved in the transfer of maternal experience to offspring. Conclusions: Our results suggest that early stickleback embryos respond to maternal exposure to predation risk via changes in gene expression, and a general acceleration of the developmental program. Further study is needed to elucidate the myriad molecular interactions between genes that are differentially-regulated as a result of maternal exposure to predation risk and to understand their relationships to previously-observed maternal effects in this system. Whole embryo mRNA profiles of 3dpf stickleback embryos of mothers exposed to simulated predation risk [E] and control mothers [C] were generated by barcoded, multiplexed high-throughput RNA-sequencing on Illumina Hiseq-2000.
Project description:Bdellovibrio bacteriovorus HD100 is a predatory bacterium which attacks a wide range of gram negative bacterial pathogens and is proposed to be a potential living antibiotic. In the current study, we evaluated the effects of indole, a bacterial signaling molecule commonly produced within the gut, on the predatory ability of B. bacteriovorus HD100. Indole significantly delayed predation on E. coli MG1655 and S. enterica KACC 11595 at physiological concentrations (0.25 to 1 mM) and completely inhibited predation when present at 2 mM. Microscopic analysis revealed that indole blocked the predator from attacking the prey. Furthermore, indole was not toxic to the predator but slowed down its motility. Microarray and RT-qPCR analyses confirmed this as the gene group showing the greatest down-regulation in the presence of 1 and 2 mM indole was flagellar assembly and motility genes. Aside from this group, indole also caused a wide spectrum changes in gene expression including the general down-regulation of genes involved in ribosome assembly and RNA translation. Furthermore, indole addition to the predatory culture after the entrance of B. bacteriovorus into the prey periplasm slowed down bdelloplast lysis. In conclusion, indole is an important gut-related signaling molecule that can have significant impacts on the predation efficiency and predator behavior. These findings should be taken into consideration especially if B. bacteriovorus is to be applied as a probiotic or living antibiotic.
Project description:Bdellovibrio bacteriovorus HD100 is a predatory bacterium which attacks a wide range of gram negative bacterial pathogens and is proposed to be a potential living antibiotic. In the current study, we evaluated the effects of indole, a bacterial signaling molecule commonly produced within the gut, on the predatory ability of B. bacteriovorus HD100. Indole significantly delayed predation on E. coli MG1655 and S. enterica KACC 11595 at physiological concentrations (0.25 to 1 mM) and completely inhibited predation when present at 2 mM. Microscopic analysis revealed that indole blocked the predator from attacking the prey. Furthermore, indole was not toxic to the predator but slowed down its motility. Microarray and RT-qPCR analyses confirmed this as the gene group showing the greatest down-regulation in the presence of 1 and 2 mM indole was flagellar assembly and motility genes. Aside from this group, indole also caused a wide spectrum changes in gene expression including the general down-regulation of genes involved in ribosome assembly and RNA translation. Furthermore, indole addition to the predatory culture after the entrance of B. bacteriovorus into the prey periplasm slowed down bdelloplast lysis. In conclusion, indole is an important gut-related signaling molecule that can have significant impacts on the predation efficiency and predator behavior. These findings should be taken into consideration especially if B. bacteriovorus is to be applied as a probiotic or living antibiotic. Bdellovibrio bacteriovorus HD100 was incubated for 30 min at 30°C in HEPES buffer supplemented with 0,1, and 2 mM indole. RNA was then extracted from each sample and purified. 100 ng of RNA from each sample were used for microarray experiment. For zero and 1 mM indole treatments, three independant samples were tested while for 2 mM indole treatment, two samples were tested. A total of 8 arrays were used.
Project description:Purpose: The goal of this study was to compare gene expression in whole embryos to identify transcriptomic changes that result from maternal exposure to predation risk. Methods: Whole embryo mRNA profiles of 3 day post-fertilizationstickleback embrosof mothers exposed to simulated predation risk and control embryos were generated by RNA-sequencing of pooled embryos using Illumina Hiseq2000. The sequence reads that passed quality filters were aligned to the stickleback reference genome and analyzed at the gene level (EdgeR) and at the transcript level (Cufflinks/Cuffdiff). Subsets of embryos were also measured for embryo length and eye diameter, and data were analyzed with a general linear model (SPSS). Results: We mapped ~22 million sequence reads per sample to the stickleback reference genome (BROADS1, Ensembl database version 71.1, Feb 2006) and identified 17440 transcripts with the Tophat workflow. Differential expression analysis using both EdgeR and Cufflinks/Cuffdiff identified 455 transcripts were differentially expressed in embryos of mothers exposed to simulated predation risk as compared to control embryos, with an FDR <0.05 (Cuffdiff) or <0.10 (EdgeR). Gene ontology and pathway analysis (DAVID, IPA) of the differentially expressed gene list revealed enrichment of genes involved in growth, metabolism, neurogenesis, and epigenetics. Embryos of mothers exposed to predation risk had elevated expression of growth and metabolism genes and were also larger than control embryos, suggesting at least some of the genes differentially expressed in this study are involved in the transfer of maternal experience to offspring. Conclusions: Our results suggest that early stickleback embryos respond to maternal exposure to predation risk via changes in gene expression, and a general acceleration of the developmental program. Further study is needed to elucidate the myriad molecular interactions between genes that are differentially-regulated as a result of maternal exposure to predation risk and to understand their relationships to previously-observed maternal effects in this system.
Project description:we studied the gene expression conditions while Drechslerella stenobrocha predates Caenorhabditis elegans. The perpose of this study is to find genes in Drechslerella stenobrocha participateing in predation. Examination of 3 transcriptomes in different predation periods to find their different gene expression style.
Project description:Venoms are complex chemical arsenals that have evolved across various animal lineages for predation, defence, and other ecological functions. In predatory species, venom composition is often shaped by diet, potentially leading to unique toxin profiles. Spiders are the most diverse group of terrestrial venomous predators, yet the venoms of most species, including highly specialized stenophagous species with narrow trophic niches, remain poorly understood. In this study, we investigated the venom of Ammoxenus amphalodes, a spider that preys exclusively on termites, to explore its molecular composition and functional adaptations. Using a proteotranscriptomic approach, we identified 116 putative toxin sequences. Half of these were cysteine-rich peptides with distinct structural motifs, most of which diverge from known spider toxins containing an inhibitor-cystine-knot (ICK) motif. The venom proteome is dominated by two ammoxotoxin families, which together account for more than half of all transcripts, supporting the hypothesis that spiders with specialized diets have lower toxin diversity. We also identified a low proportion of larger venom proteins, including cholinesterases, phospholipases, immune proteins, carbonic anhydrases, and EF-hand proteins, which may serve housekeeping functions or play auxiliary roles in prey incapacitation. Bioassays with selected lab-produced peptides revealed one prey-specific peptide, U-AXTX(9)-Aa15, a member of the waprin family, which paralyses termites but not flies. The other peptides tested showed limited prey specificity, challenging assumptions of venom specialization. These findings provide new insights into the evolution of venom in dietary specialists and broaden the search for novel bioactive compounds with potential biotechnological applications.